Matthew91-Z28

hey all....would love som advice about what to do here. Planning some major engine/drive-train/tranny work in about a month.

Going from a 305 to a crate 350,
switching 700R4 to a T5-6
new drive shaft,

Anyway, I think I'm pretty sure I have a 2.73 in my 91 convertable Z28 (305). Probably will be running around 340 hp. WHat gears should I get for the rear? I'm thinking 3.23 but not sure. And, will a 4th gen rear work on mine??

87RS402

if you use a 93 or aftermarket T-56, 3.73 's. For 94-97 T-56's you'll be alot happier with 4.10's.

sIcK pUpPy

I agree with 87RS402. 4.10's are the best way to go when using a T-56. Just check on www.LS1.com That's what they're using.

JD

Momar

My friend is planning on swapping from a 700r4 to a t56 and he is planning on doing this before he changes his gears. The thing is, he has a 2.77 borg warner rear. I know about the cost of the parts for it and so does he. That is part of the reason he wants to do the tranny first. My question is how will the 2.77s work with the t-56. I know for acceleration 4:10s are recomended, but will it be drivable. I imagine he will be going with a 94 plus tranny for strength issues.

Thanks for the help

Ben

Matthew91-Z28

What are stock 6-speed 4th gen Trans Am's and Camaro's equipped with in the rear?

Momar

Im not sure, I think at least 3.23s, but I think at least some if not all came with 3.42s.

Ben

sIcK pUpPy

Matthew,
3.42's from the factory, but everyone (T-56'rs) that changes gears in the 4th gens end up going with 4.10's.


JD

Matthew91-Z28

thanks...I have a direction now. I'll look into those 4.10's. You guys have helped alot. I'll keep you posted on the works in progress. :hail:

soulbounder

How much would 4.10s hinder top speed compared to 3.42s or 3.73s? Any percentage figures?

sIcK pUpPy

I don't have the figures, as I get all my 4th gen info from my friend (runs a '99 Ram Air T/A). I will look into it and post the data when I get the time. Again, check out this link www.ls1.com it will contain everything you wanted to know about the 4th gens, but were afraid to ask.

Lates,
JD

JAY87GTA

If you get a 94-97 tranny with the .50 overdrive and 4.10 gears it would be the equivalent of running a 2.05 rear with a 350turbo. If you have 3.27 gears and a 700R4 now it's the equivalant of running a 2.28 rear. Only now you can hold it wide open in 6th gear and you still probably won't run out of gear before you do courage or sense.

BOTTLEDZ28

iTrader: (9)

I have had experiance with both 4.10 and 3.73 gears behind a T56. My first was a 97 trans am with 4.10's. I went from the factory 3.42 to the 4.10's and it was great. you can use 6th gear now at reasonalbe speeds. They didnt last long though. THe 4.10's put a lot of stress on the rear and I ended up ripping 7 teeth off the ring gear at the end of a 1/4 mile run. It wasnt fun. I **** my pants. I now have a 91z28 with a 350tpi and the T56. I put a 4th gen rear in it and used the 3.73's instead. Sometimes I feel like I should have gone to 4.10's but I just dont want to worry about the weak 10 bolt getting abused. ang the gas prices dont look like there coming down soon so maybe the 3.73 where a better choice for me. you should definitly get a rear cover with studs in it too strenthen the rear

Ukraine Train

my friend has 2.73s with a t56 for now and at 70mph turns 1200rpm. he has to shift to fifth to accelerate even a little.

did thirdgen axles with pbr brakes come with 3.73s? that's what i want to use when i do the t56 swap but if not then i'll try to get 3.42s and maybe swap them to 3.73s down the line.

Momar

I dont think that 3.73s came in any of the thirdgens after 84 and the pbr brakes started in 89. I just put pbr brakes on a 3.45 9 bolt and trust me, it gets expensive quick. You would be better off if you are going to use a 10 bolt to get one with the brakes on it and put the gears in.

Ben

Matthew91-Z28

yeah. I decided to find a complete 4th gen rear with the brakes on it. Since 3.42's were stock, that may be all I'm able to find. But thats ok; gas won't eat my lunch so much.